LT77 Gearbox Identification

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joshls
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Re: LT77 Gearbox Identification

Post by joshls »

Hi,
I have what I believe to be an LT77 gearbox. I'm having similar issues identifying what it's from. There isn't the typical serial number i was expecting, instead it has these engraved figures on the bottom of the casting. 19A22531A
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GDCobra
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Re: LT77 Gearbox Identification

Post by GDCobra »

joshls wrote:
Sun May 02, 2021 5:51 pm
Hi,
I have what I believe to be an LT77 gearbox. I'm having similar issues identifying what it's from. There isn't the typical serial number i was expecting, instead it has these engraved figures on the bottom of the casting. 19A22531A
That’s not where the number is found in my experience, it’s normally on a flat machined, oval-ish, area on the side of the main casing (right hand I think)

richyb66
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Re: LT77 Gearbox Identification

Post by richyb66 »

The oval pad on the side of the main casing with the serial number stamped on it is only on suffix C boxes onwards. Suffix A and B have the number stamped underneath.

Suffix A and B have smaller bearings on the first motion shaft so not as robust as the later boxes. Even a good one (if you can find one) is probably marginal behind a standard V8. Generally once the first motion shaft bearing go, the box is scrap.

19A22531A would be very early SD1 V8, I've rebuilt quite a few LT77s and I generally avoid anything pre-suffix C because some of the earlier parts aren't available and I've not found on yet that was worth rebuilding.

joshls
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Re: LT77 Gearbox Identification

Post by joshls »

Thank you, really appreciate the reply!

minorv8
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Re: LT77 Gearbox Identification

Post by minorv8 »

I ran a LT77 from a 2-litre TR7 behind a 3,5 Rover that eventually got replaced with various versions of 4,6 litre engine. I had no issues with the box even though it is supposed to be the weakest version. I did rebuild it when I built the car in late 90´s.

I replaced it last winter with a BMW 6-speed box for better ratios, otherwise the LT77 is still in perfect condition. But, it is old, parts are difficult to get or NLA, maybe even a bit agricultural. But it did survive easily in a light car like mine. There is never enough traction to really load the box. OK, you can break anything if you really try...

stevieturbo
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Re: LT77 Gearbox Identification

Post by stevieturbo »

This was the last LT I used a couple of decades or more ago lol......think it was a 2.0 version. It barely lasted one blast up the road lol
DSC01587.JPG
DSC01586.JPG
DSC01585.JPG
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

minorv8
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Re: LT77 Gearbox Identification

Post by minorv8 »

It barely lasted one blast up the road lol
With a std engine of course :lol:

unstable load
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Re: LT77 Gearbox Identification

Post by unstable load »

My R380 from my Discovery Td5 after it ate itself thanks to a chafed through oil cooler pipe....
R380.jpg
R380 2.jpg
Cheers,
John

jp928
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Re: LT77 Gearbox Identification

Post by jp928 »

Have a 25A box - cant find the prefix anywhere? Needs rebuilding.
jp 74 P6B S b

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